The present invention is directed to a panelized drum system and, more particularly, to rotating drums as well as methods and apparatuses for fabrication of rotating drums using a panelized design and the principles of mass production and distribution.
Rotating drum composters (also known as “in-vessel composters”) were first patented in 1870. Since then there have been over 177 patents issued in the United States for some part of the composting process. Exemplary composters are discussed in the following patents:
U.S. Patent No.Issue DateApplicant(s)2,948,593Apr. 15, 1957Larson3,245,759Apr. 12, 1966Eweson3,930,799Jan. 6, 1976Eweson5,047,349Sep. 10, 1991Eweson5,169,782Dec. 8, 1992Murphy et al.5,407,809Apr. 18, 1995Finn6,110,733Aug. 29, 2000SeymourThe disclosures of the patents listed above are hereby expressly incorporated herein by reference in their entirety. These known composters can be divided into three categories: small composters, medium composters, and large composters. All the known composters have been fabricated one composter at a time. The known fabrication process for making a steel drum for small composters and medium composters comprises the following steps:                cutting steel plates the length of the desired circumference of the sub-cylinder(s) that will form the body of the drum;        rolling steel plates (putting a curve into flat plate—usually there is a section on both ends of the plate that is not rolled because of the limitation of the rolling machine),        welding the ends of the steel plates together to form the sub-cylinder, and        re-rolling the sub-cylinder to make it substantially round.These steps are repeated until there are enough sub-cylinders to make the body of the drum (the “drum cylinder”). (It should be noted that because metal tends to stretch, in practice these sub-cylinders are rarely the same size. Also the process of re-rolling can be imprecise.) These sub-cylinders are then stacked end-to-end and welded together to form the body of the drum. (It should be noted that the welding process can correct some of the size and shape discrepancies between the sub-cylinders.) Typically, there are temporary fixtures that are placed inside the drum cylinder to achieve roundness. The drum cylinder is then capped on each end to create a drum. Doors and other accessories are then added to the drum and the complete drum is then sub-arc welded. Then the drum is sent to be painted and insulated. Significantly, known drums are fabricated one unit at a time and are virtually complete before they are painted and insulated. The typical rotating drum is rotated using systems such as a direct rotational drive system (such as a sprocket and chain drive), a large bull gear around the drum and a pinion gear, or those shown and described in the above incorporated references.        
The small rotating drum composters are generally of a size that is easily transported from one place to the other. Small rotating drum composters are not very cost efficient.
The next size would be the medium rotating drum composters. Medium rotating drum composters are units that are still made the same way but these are not easily transported. They require special permits and equipment to transport them to the end user. Shipping medium rotating drum composters costs from $6,000 to $30,000.
The final size units are large rotating drum composters. These units are still manufactured in the same way but, because of their size, they cannot be transported after they have been fully assembled. Accordingly, large rotating drum composters are fabricated and welded together in the field (e.g. generally in a large area near a source of composting raw material). (For purposes of this disclosure, “in the shop” is defined as any process that takes place at the facility in which the product is made and “in the field” is defined as any place other than in the manufacturing facility (the shop) where the drum is to be located and used.) Even the painting and insulation has to be done in place, because once these large rotating drum composters are complete, they cannot be moved. This is an expensive and time-consuming process and is very weather dependant.